In recent years, a field sequential type display device has been attracting attention as a new type display device which performs color display. In a typical field sequential type display device, one frame period is divided into three subfield periods corresponding to red, green, and blue. In a red subfield period, a light modulation section is driven based on a red video signal, and a red light source emits light. With this, a red subfield is displayed. Similarly, a green subfield is displayed in a green subfield period, and a blue subfield is displayed in a blue subfield period. Color display can be performed by displaying the red, green, and blue subfields in a switching manner at high speed.
The field sequential type display device does not have a color filter. Therefore, it is possible to improve light utilization efficiency and realize a background transparent type display device. Furthermore, the field sequential type display device performs color display using one type of pixels instead of red, green, and blue subpixels. Therefore, it possible to reduce a number of pixels required for performing color display and realize a high resolution display device.
In a field sequential type display device which displays the red, green, and blue subfields in one frame period, when an observer's line of sight moves in a display screen, the observer may see colors of each subfield separately (this phenomenon is hereinafter referred to as color break). As a method for reducing the color break, there is known a method in which a subfield corresponding to a mixed color such as white, yellow, cyan, and magenta is displayed in addition to the red, green, and blue subfields in one frame period. In a mixed color subfield period, two or more of the red light source, a green light source, and a blue light source emit light.
Patent Document 1 describes a field sequential type liquid crystal display device which displays red, green, blue, and white subfields in one frame period in order to suppress the color break. In a white subfield period, the red light source, the green light source, and the blue light source emit light Patent Document 1 discloses a method for obtaining a video signal of four colors (red, green, blue, and white video signals) corresponding to each subfield, based on an input video signal of three colors (red, green, and blue video signals).